SimpleRCDelayCalc.cc

// OpenSTA, Static Timing Analyzer
// Copyright (c) 2020, Parallax Software, Inc.
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

#include "SimpleRCDelayCalc.hh"

#include "TimingArc.hh"
#include "Liberty.hh"
#include "Network.hh"
#include "Sdc.hh"
#include "Parasitics.hh"
#include "DcalcAnalysisPt.hh"

namespace sta {

ArcDelayCalc *
makeSimpleRCDelayCalc(StaState *sta)
{
  return new SimpleRCDelayCalc(sta);
}

SimpleRCDelayCalc::SimpleRCDelayCalc(StaState *sta) :
  RCDelayCalc(sta)
{
}

ArcDelayCalc *
SimpleRCDelayCalc::copy()
{
  return new SimpleRCDelayCalc(this);
}

void
SimpleRCDelayCalc::inputPortDelay(const Pin *port_pin,
				  float in_slew,
				  const RiseFall *rf,
				  Parasitic *parasitic,
				  const DcalcAnalysisPt *dcalc_ap)
{
  pvt_ = dcalc_ap->operatingConditions();
  RCDelayCalc::inputPortDelay(port_pin, in_slew, rf, parasitic, dcalc_ap);
}

void
SimpleRCDelayCalc::gateDelay(const LibertyCell *drvr_cell,
			     TimingArc *arc,
			     const Slew &in_slew,
			     float load_cap,
			     Parasitic *drvr_parasitic,
			     float related_out_cap,
			     const Pvt *pvt,
			     const DcalcAnalysisPt *dcalc_ap,
			     // Return values.
			     ArcDelay &gate_delay,
			     Slew &drvr_slew)
{
  drvr_parasitic_ = drvr_parasitic;
  drvr_rf_ = arc->toTrans()->asRiseFall();
  drvr_cell_ = drvr_cell;
  drvr_library_ = drvr_cell->libertyLibrary();
  pvt_ = pvt;
  LumpedCapDelayCalc::gateDelay(drvr_cell, arc, in_slew,
				load_cap, drvr_parasitic, related_out_cap,
				pvt, dcalc_ap,
				gate_delay, drvr_slew);
}

void
SimpleRCDelayCalc::loadDelay(const Pin *load_pin,
			     ArcDelay &wire_delay,
			     Slew &load_slew)
{
  ArcDelay wire_delay1 = 0.0;
  Slew load_slew1 = drvr_slew_;
  bool elmore_exists = false;
  float elmore = 0.0;
  if (drvr_parasitic_)
    parasitics_->findElmore(drvr_parasitic_, load_pin, elmore, elmore_exists);
  if (elmore_exists) {
    if (drvr_library_ && drvr_library_->wireSlewDegradationTable(drvr_rf_)) {
      wire_delay1 = elmore;
      load_slew1 = drvr_library_->degradeWireSlew(drvr_cell_, drvr_rf_,
						  pvt_,
						  delayAsFloat(drvr_slew_),
						  delayAsFloat(wire_delay1));
    }
    else if (parasitics_->isReducedParasiticNetwork(drvr_parasitic_))
      dspfWireDelaySlew(load_pin, elmore, wire_delay1, load_slew1);
    else {
      // For RSPF on an input port the elmore delay is used for the
      // wire delay and the slew is copied from the driver.
      wire_delay1 = elmore;
      load_slew1 = drvr_slew_;
    }
  }
  thresholdAdjust(load_pin, wire_delay1, load_slew1);
  wire_delay = wire_delay1;
  load_slew = load_slew1 * multi_drvr_slew_factor_;
}

} // namespace